from collections import deque, defaultdict, Counter
from bisect import bisect_left, bisect_right
from itertools import permutations, combinations, groupby
from heapq import heappop, heappush
import math, sys
input = lambda: sys.stdin.readline().rstrip("\r\n")
def printl(li, sep=" "): print(sep.join(map(str, li)))
def yn(flag): print(Yes if flag else No)
_int = lambda x: int(x)-1
MOD = 998244353 #10**9+7
INF = 1<<60
Yes, No = "Yes", "No"

S = input()
N = len(S)
A = []
ans = 0
for i in range(N):
    if S[i] == "A":
        A.append(i)
        ans += 1

cnt = 1
for i in range(N):
    if S[i] == "M":
        acnt = len(A) - bisect_left(A, i)
        ans += cnt*acnt*2
        ans %= MOD
        cnt *= 3
        cnt %= MOD
print(ans)